1. Field of the Invention
The present invention relates to improved methods for removing and reinstalling bottom entering agitator seals, and more particularly, but not by way of limitation, to a method of removing and reinstalling a seal unit from a process vessel bottom entering agitator assembly wherein a jack is connected in the assembly to facilitate the removal of the seal unit.
2. Description of the Prior Art
Process vessels are commonly utilized in refineries, chemical plants and the like which include internal agitators. In a number of such vessels, the agitator within the vessel is driven by a vertical shaft which extends through an opening at the bottom of the vessel. A seal unit is provided connected to the vessel which prevents reactants or other fluids within the vessel from leaking out of the vessel around the agitator drive shaft. The seal unit is connected to a coupling shaft which is in turn connected to a rotary drive means such as an electric motor operably connected to a right angle gear box.
The seal units of large agitator assemblies are heavy, i.e., they often weigh over a thousand pounds, and when it is necessary to repair or replace such units, the removal and reinstallation thereof has been very difficult. Heretofore, the procedure followed for removing the seal unit from a vertically positioned bottom entering agitator assembly has been to remove the coupling shaft extending between the seal unit and the rotary drive means and then to lower and raise the seal unit, agitator shaft and agitator attached thereto in order to secure the agitator and agitator shaft within the vessel and remove the seal unit therefrom using a forklift truck having a special platform attached to the forks. The platform is positioned under the seal unit and bolted to the bottom end thereof. Because the weight of the seal unit, agitator shaft and agitator is carried off center on the fork truck, the load on the fork truck is unstable and causes the seal unit to tip and bind on guide rods. This situation presents a serious safety hazard.
By the present invention an improved method of removing and reinstalling seal units in bottom entering agitator assemblies is provided whereby the use of a forklift truck and the hazards attendant thereto are obviated.